The proposed project is part of a long term interdisciplinary effort of elucidation of the nature and underlying mechanisms of menstrually related changes. The present focus is the degree of premenstrual change in cognitive and psychomotor functions in some women. It has been shown that while most women do not have significant cyclic cognitive changes, some women, especially those with premenstrual dysphoria - consistently report such changes. Our preliminary data point that these changes may be objectively confirmed. They are probably in complex coordinated tests and might be associated with changes in levels of gonadal hormones. The project is aimed at: 1) Objective confirmation (or disconfirmation) of premenstrual changes of cognitive functions in women who complain of such changes; 2) Investigation of the influence of gonadal and pituitary hormones on the functions in focus. 3) Clarification of the association of premenstrual cognitive changes with premenstrual dysphoria; 4) elucidation of a possible selection diversity of premenstrual cognition and psychomotor functions; 120 Women who seek treatment for premenstrual dysphoria, (60 who report cognitive changes and 60 who do not report such changes) and 30 women with no PMC will be tested at mid-follicular phase and late luteal phase. The battery of 8 tests has been designed to cover a wide range of cognitive and psychomotor functions with a wide range of complexity. Hormonal plasma levels as well as mood and behavior will be assessed every morning prior to the tests. Women whose dysphoric PMC will be found severe enough to warrant treatment will enter into one of the treatment protocols aimed at elimination of ovulation and hormonal fluctuation by creating different hormonal environments (Danocrine, ethinyl estradiol and triphasil). Changes in psychomotor and cognitive functions under these conditions will be compared to pretreatment baselines. The proposed project should lead to better understanding of the influence of pituitary and gonadal hormones on cognitive and psychomotor performance. It will also contribute to settle the sex bias originating from stereotyping entire population based on impressions derived from few individuals.